Operating Temperature and junction temperature.

Sep 07, 2007 1 Replies

Hi all,



I am working with thermal analysis of a PCB for the first time. I have some preliminary doubts regarding same.


  1. What is difference between the operating temperature range and junction temperature.
  2. Why operating temperature is less than that of junction temperature.
  3. While calculating component failure at particular ambient condition should we consider junction temperature as threshold value or amblient temperature as threshold value.

Looking forward for your replies.



Regards, Asmita



1) When I work out in a hot gym, its air temperature might be 80 degF My temperature underarm is about 98degF 2) I am exothermic, so my underarm junction temp is higher than the air ambient operating temp 3) For components, junction temps may vary, but they are all specified for some max ambient.

Brian W

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